A full direct-connection manner of PCB boards proposed by the IBM company implements the interconnection between CPUs. Each IBM Power CPU has seven high-speed interconnect interfaces, and may be interconnected to seven Power CPUs at the same time. Eight Power CPUs may form an 8P system in the full direct-connection manner. However, since the Power CPU is integrated with functions of an NC controller, the cost is relatively high. Limited by the number of the Power CPU interconnect interfaces, a CPU system formed by the Power CPUs has poor scalability and low flexibility.
The HP company adopts an NC node controller and a switch module to implement the interconnection between CPUs, and the whole system of the interconnect architecture is complex. In the solution, two chips are added in the whole system, which implement the function of the NC node controller and the function of the switch module, respectively. Since the switch module is used for data exchange among NCs in the solution, each switch module needs to perform jump-point judgment, which increases data transmission delay, resulting in low system performance and a high cost.
Therefore, the existing interconnect system among CPUs has poor scalability, long data transmission delay, and a high cost.